[NASSP 8][Apollo 8] Realtime simulation preparation

[STS]

Dear all,

Since I completed the RTS of Apollo 7, I am preparing the next one, Apollo 8. As you know my goal is to make one of these every 6 months. Apollo 8 is ready on the launchpad for an may 18 launch.

As on the Apollo 8 training last year and on Apollo 7, I will lift-off at 7:51 CEST (Central European Summer Time), as the real mission lifted off at 7:51 EST (Eastern Standard Time) and I believe that is the time that the crew had on their watches (correct me if wrong, please, as I don´t know if they were synced with Houston time, wich I think was on another timezone).

So now for the questions as I will focus now on training of specific tasks for the mission (did the whole mission from december to march and wanted to do another run but I don´t have the time )

• P23: My main issue with P23 is that I can´t keep a "killrot" attitude (and maybe I can´t do that because I am travelling fast and that causes the earth/moon horizon to move around) and roll doesn´t stay still.

About the P23 questions, I will post a few videos explaining my difficulties. I will also check pages 78-103 of https://www.ibiblio.org/apollo/Documents/E-2448-REV0.pdf

• Housekeeping procedures: On the flightplan, ECS redundant component checks or waste dumps do not appear. So the question is: When should I do the first? In what interval of hours? On Apollo 7 it was done periodically. For the waste dumps, I assume that I can do them on discretion, and before and after sleep. Maybe on discretion I can also do SPS/RCS monitoring checks, EPS systems checks, etc...

So I think that is it for the moment, will be adding more questions as I find them.

Best regards,

 

[CaptainSwag101]

Hey there! I recently flew an Apollo 8 mission myself a couple months back, and I can share your sentiments about difficulties with keeping your roll movement under control. I believe this is because there's a lot less inertia in the roll axis due to the shape of the spacecraft being relatively cylinder-shaped. In addition, since you don't have a Lunar Module attached to the spacecraft, that also further reduces the inertia and causes fine-tuning of your attitude rates to be rather tricky. My primary suggestion would be to maneuver to the P23 attitude early on and give the spacecraft's DAP time to stabilize the attitude over the span of several minutes, if possible. The procedures for PTC (passive thermal control) usually instruct the astronauts to wait a whole 20 minutes after maneuvering to the PTC attitude before beginning the roll maneuver, to ensure that the spacecraft had plenty of time to dampen its rates. With all that said, I should honestly note that I skipped most of the P23 operations because I found them very difficult; they require plenty of practice and I believe even the astronauts themselves had some trouble with them. So take my advice with a few grains of salt.

 

[abr35]

For P23, P52, etc you use the following to limit unwanted rates:

S/C Cont - SCS
Att Deadband - Min
Rate - Low
BMAG (3) - Att 1/Rate 2
I've found limit cycle can help too if you dont want to maneuver.

This usually will keep the rates managable provided you're using rate command or minimum impulse.

Avoiding 4 jet roll also helps.

Also - what CaptainSwag said. In the technical debriefs the astronauts often called the CSM 'sporty' when no LM was attached.

 

[Max-Q]

P23: My main issue with P23 is that I can´t keep a "killrot" attitude

If you don’t mind cheating a bit, you can use the killrot option in PAMFD… I justify this kind of thing because the real astronauts trained for years for their missions…

 

[rcflyinghokie]

If you don’t mind cheating a bit, you can use the killrot option in PAMFD… I justify this kind of thing because the real astronauts trained for years for their missions…

Or just use the minimum impulse controller and configure for 2 jet roll to null small rates like the crew actually did? I personally am not a fan of killrot as it really takes from the immersion to me.

 

[MrFickles]

CMC Hold should work too right?

 

[rcflyinghokie]

CMC Hold should work too right?

For holding attitude within a tight deadband yes, but not for maneuvering during P23

 

[STS]

CMC Hold should work too right?

Yeah, that is what I switch to after the Auto Maneuver completes, but earth/moon horizon keeps moving (just a little bit, but enough to be unconfortable and cause bad results).

As I said I will post some descriptive videos. Maybe this weekend...

 

[STS]

Thanks all for your feedback regarding P23; I will not worry too much about it then, we will see how it goes during the mission and ask you there if required. We will do all the runs, and there are a lot of them

Quick question: During Prelaunch checks, the ΔV CG switch position is checked (Panel 1). On the checklist I have, it is set to LM / CSM . But on Apollo 7 and 8 there is no LM, so would it be correct to set it to the down position (CSM)?

Quick note: Just checked this picture (while writing this post):

https://history.nasa.gov/diagrams/ad019b.gif

The label there is LV / CSM, wich would make more sense if the switch has to be in the up position. Is this a typo on the NASSP´s label?

Best regards,

 

[indy91]

Quick question: During Prelaunch checks, the ΔV CG switch position is checked (Panel 1). On the checklist I have, it is set to LM / CSM . But on Apollo 7 and 8 there is no LM, so would it be correct to set it to the down position (CSM)?

Quick note: Just checked this picture (while writing this post):

https://history.nasa.gov/diagrams/ad019b.gif

The label there is LV / CSM, wich would make more sense if the switch has to be in the up position. Is this a typo on the NASSP´s label?

Not a typo in NASSP, the switch says LM/CSM. Must be a typo in your source. The switch affects the behavior of the SCS Auto TVC. It is set to LM/CSM for launch, at least for heavy CSMs, for the following reason given in the AOH Volume 2: "Provides reduced gain for SPS thumbwheel control of SCS auto mode IV abort".

With the LM/CSM position of the switch the SCS Auto TVC will reduce an attitude error during a SPS burn more slowly and "carefully". And I guess that is desired behavior during a possible Mode IV abort. Once you are doing your first normal SPS burn all the switches are checked as part of the checklist, then you can set it to the CSM position for Apollo 8 because normally you do want the switch to be in the correct position for CSM vs. CSM+LM.

 

[STS]

Hello all,
Getting ready for the mission. When practicing SEP & Transposition, I found myself with a black S-IVB "LM Adapter":
Is this an issue because of shadows? Is this the correct color? Do I have a texture issue?

I was running release 1881.

Best regards,

 

[Max-Q]

I found myself with a black S-IVB "LM Adapter":
Is this an issue because of shadows? Is this the correct color? Do I have a texture issue?

Looks like the fwd end of the S-IVB is in shadow. I made the LTA mesh, and it doesn't use textures, no no texture issue. The big metal part should be light grey and the struts a darker grey. To test and see if it looks right, try turning on the "Add Ambient Light" option in D3D9 Debug Options.

I think the real CSM had a floodlight to illuminate the S-IVB (and later, the LM) during T&D (Don't quote me on that!)

 

[rcflyinghokie]

I think the real CSM had a floodlight to illuminate the S-IVB (and later, the LM) during T&D (Don't quote me on that!)

Indeed it did have a forward facing spotlight, but TDE maneuvers were also designed to have some sun illumination of the SIVB as well

 

[Max-Q]

Indeed it did have a forward facing spotlight

Any plans to get it working in NASSP? The switch is there…

 

[rcflyinghokie]

Any plans to get it working in NASSP? The switch is there…

Absolutely, IIRC there are limitations on orbiter and lighting though which would be part of the battle. The electronics and stuff would be easy.

I will add a git issue to keep it in mind

EDIT: Added https://github.com/orbiternassp/NASSP/issues/776

 

[n72.75]

Absolutely, IIRC there are limitations on orbiter and lighting though which would be part of the battle. The electronics and stuff would be easy.

I will add a git issue to keep it in mind

EDIT: Added https://github.com/orbiternassp/NASSP/issues/776

We can do it, but we have a maximum number of lights of 8. I think even with eventual interior lighting we can do this.

Exterior lights
CSM Spotlight
CSM Rendezvous light
CSM eva light
LM tracking light

Interior lights
CSM, left, right, and LEB
LM 2 overhead

That's a fairly full list, and it's only 9. There would be virtually no instances where you would have all of these on and visible at the same time.

 

[STS]

Hello all,

Just completed the training of the 26-ish hours of activity of FD-4! (The lunar day).
Now focusing on reentry. On the "Apollo 8 - 12 - Entry Preparations T+142h40min.scn" scenario I get first a Suit Compressor light, then it turns off and then a Cryo Press alarm and then I observed that the Cabin pressure is increasing and the Cabin temperature skyrockets up.

Is there an issue on this scenario? Running 1881.

Best regards

 

[rcflyinghokie]

Hello all,

Just completed the training of the 26-ish hours of activity of FD-4! (The lunar day).
Now focusing on reentry. On the "Apollo 8 - 12 - Entry Preparations T+142h40min.scn" scenario I get first a Suit Compressor light, then it turns off and then a Cryo Press alarm and then I observed that the Cabin pressure is increasing and the Cabin temperature skyrockets up.

Is there an issue on this scenario? Running 1881.

Best regards

Premade scenario files have not been updated to some of the systems changes we have made so later mission saves you will see a lot of ECS transients and issues like this. Its simply a matter of you using an outdated scenario file. Until we recreate them you will see this issue in many of the pre saved files. Of course launch scenarios from scratch will not run into these problems.

 

[CaptainSwag101]

Still very excited to see this happen, whenever the time is right. I know you use the 3D virtual cockpit for your simulations, and I hope that the new DSKY/numerical digits are still legible in the VC. They look nice in the 2D cockpit and are relatively bright but I had a very tricky time making them look good in the VC. I think I ironed out all the bugs, though!

 

[Max-Q]

I almost exclusively use the VC, and they look excellent. Awesome work!